Monster Briggs Stroker Build!

Ibanez616

Ibanez616

Member
#1
#1
Time for an adventure in engine building. I am putting a .563 stroker crank in a BRIGGS block. This engine will end up being the equivalent of a blockzilla in briggs clothing. So heres my parts list so far:
Briggs Bearing block .10 over, lifter area welded, HEAVILY clearanced
Pure Power .563 (7/8 journal) stroker crank
Dyno 126 cam
ARC 4.225 or 4.275 rod
Wiseco 1991 piston
Alky Tillotson Carb
Dyno Green Stripe Springs
Big Valves
3hp Flywheel

I will post updates periodically as I am working on this project. I am still undecided on a few parts of this project like header, length of lifters, size of valves, spark plug, and a few other small things. Any and all input is appreciated. Let the fun (and grinding) begin! :grind:
 
Ibanez616

Ibanez616

Member
#2
#2
Part I; Getting the parts and starting the build.

Today i got some parts i bought from eBay in the mail.


Here is a quick mock up just to see that everything "fits".


You can see here that the piston is just under the deck with the 4.225 rod. With the 4.275 rod, the piston slightly protrudes over the deck.
 
Ibanez616

Ibanez616

Member
#3
#3
Part II; Clearancing

To just get the crank to make a full 360 degree turn in the block i had to remove some material on this top left corner area.


Now with the rod attached to the crank, the rod bolt and dipper hit the side of the block, more clearancing needed.


A mock up of what it looks like so far, more progress tomorrow.
 
minidragbike

minidragbike

Supporting Speed Nut!
#5
#5
It should make a good amount of power when done. But make sure you put a block girdle on it. The block is very easy to break in half with a large crank in it.

Now what size valves and carb are you gonna run?
 
minidragbike

minidragbike

Supporting Speed Nut!
#8
#8
Maybe 25hp if done correctly
1.250" intake, with 1.125" exhaust
28mm mikuni, or HL380 tillotson carb
Also on the porting you want the intake to be 1.125" I.D. and exhaust port 1" I.D
 
Ibanez616

Ibanez616

Member
#11
#11
Part II; Clearancing (Countinued)

Today's progress, a nice bit of metal removed from my once virgin block, no turning back now. Here's the lifter side, the reason for removing material here is that the rod made contact in that area and would cause the rotating assembly to lock.


And here's both sides almost finished, the left side just needs a bit more clearance.


So in conclusion, after today's work I now have the crank, rod and piston turning unobstructed. Since this is my first time doing this sort of thing i am learning as I go along. Tomorrow I start dealing with the cam. To you builders, welders or anyone in general who can answer this question, from what you see would you trust the welding on the lifter bore area?
 
minidragbike

minidragbike

Supporting Speed Nut!
#14
#14
Ibanez616 said:
This block came pre-welded. And i know i have to relieve the lifter bores.
Click to expand...
He aint lying, with a stroke that big you gotta almost have everything welded. Your cam will need to be billet, and it will almost cut right through the center. Grind the bottom of the bore, inside of the front of the block, grind the crank itself, and maybe grind the rod a little.
 
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